a curious look at the brain, how it works, and what happens when its best-laid plans go awry

It may not be lack of empathy or fear of consequences, as previously postulated, but rather a hyper-active attraction to reward and risk. Researchers suspect this heightened draw may be the result of an exaggerated dopamine responses produced by an overactive nucleus accumbens.

In the first portion of the experiment, the researchers gave the volunteers a dose of amphetamine, or speed, and then scanned their brains using PET to view dopamine release in response to the stimulant. Substance abuse has been shown in the past to be associated with alterations in dopamine responses. Psychopathy is strongly associated with substance abuse.“Our hypothesis was that psychopathic traits are also linked to dysfunction in dopamine reward circuitry,” Buckholtz said. “Consistent with what we thought, we found people with high levels of psychopathic traits had almost four times the amount of dopamine released in response to amphetamine.”

In the second portion of the experiment, the research subjects were told they would receive a monetary reward for completing a simple task. Their brains were scanned with fMRI while they were performing the task. The researchers found in those individuals with elevated psychopathic traits the dopamine reward area of the brain, the nucleus accumbens, was much more active while they were anticipating the monetary reward than in the other volunteers.

“It may be that because of these exaggerated dopamine responses, once they focus on the chance to get a reward, psychopaths are unable to alter their attention until they get what they’re after,” Buckholtz said. Added Zald, “It’s not just that they don’t appreciate the potential threat, but that the anticipation or motivation for reward overwhelms those concerns.”

Scientists have found that blocking the ability to move the body causes changes in cognition and emotion, but there were always questions. (One of the test treatments caused widespread, if temporary, paralysis.) In contrast, Havas was studying people after a pinpoint treatment to paralyze a single pair of “corrugator” muscles, which cause brow-wrinkling frowns.

To test how blocking a frown might affect comprehension of language related to emotions, Havas asked the patients to read written statements, before and then two weeks after the Botox treatment. The statements were angry (“The pushy telemarketer won’t let you return to your dinner”); sad (“You open your email in-box on your birthday to find no new emails”); or happy (“The water park is refreshing on the hot summer day.”)

Havas gauged the ability to understand these sentences according to how quickly the subject pressed a button to indicate they had finished reading it. “We periodically checked that the readers were understanding the sentences, not just pressing the button,” says Havas.

The results showed no change in the time needed to understand the happy sentences. But after Botox treatment, the subjects took more time to read the angry and sad sentences. Although the time difference was small, it was significant, he adds. Moreover, the changes in reading time couldn’t be attributed to changes in participants’ mood.

The use of Botox to test how making facial expressions affect emotional centers in the brain was pioneered by, Andreas Hennenlotter of the Max Planck Institute in Leipzig, Germany.

“There is a long-standing idea in psychology, called the facial feedback hypothesis,” says Havas. “Essentially, it says, when you’re smiling, the whole world smiles with you. It’s an old song, but it’s right. Actually, this study suggests the opposite: When you’re not frowning, the world seems less angry and less sad.”

The Havas study broke new ground by linking the expression of emotion to the ability to understand language, says Havas’s advisor, UW-Madison professor emeritus of psychology Arthur Glenberg. “Normally, the brain would be sending signals to the periphery to frown, and the extent of the frown would be sent back to the brain. But here, that loop is disrupted, and the intensity of the emotion, and of our ability to understand it when embodied in language, is disrupted.”

Practically, the study “may have profound implications for the cosmetic-surgery,” says Glenberg. “Even though it’s a small effect, in conversation, people respond to fast, subtle cues about each other’s understanding, intention and empathy. If you are slightly slower reacting as I tell you about something made me really angry, that could signal to me that you did not pick up my message.”

To better understand its neurobiology, Feusner and colleagues examined 17 patients with BDD and matched them by sex, age and education level with 16 healthy people. Participants underwent functional magnetic resonance imaging (fMRI) while viewing photographs of two faces — their own and that of a familiar actor — first unaltered, and then altered in two ways to parse out different elements of visual processing.

One altered version included only high-spatial frequency information, which would allow detailed analysis of facial traits, including blemishes and hairs. The other showed only low-spatial frequency information, conveying the general shape of the face and the relationship between facial features.

Compared to the control participants, individuals with BDD demonstrated abnormal brain activity in visual processing systems when viewing the unaltered and low-spatial frequency versions of their own faces. They also had unusual activation patterns in their frontostriatal systems, which help control and guide behavior and maintain emotional flexibility in responding to situations.

Brain activity in both systems correlated with the severity of symptoms. In addition, differences in activity in the frontostriatal system varied based on participant reports of how disgusting or repulsive they found each image. Basically, how ugly the individuals viewed themselves appeared to explain abnormal brain activity in these systems.

The abnormal activation patterns, especially in response to low-frequency images, suggest that individuals with body dysmorphic disorder have difficulties perceiving or processing general information about faces.

“This may account for their inability to see the big picture — their face as a whole,” Feusner said. “They become obsessed with detail and think everybody will notice any slight imperfection on their face. They just don’t see their face holistically.”